This is not a great article. These "stats" as he calls them are a poor measure of this. Now I'm not saying Erb doesn't play any part of this, but how can you blame Kaz, then when his numbers are not that bad and actually better than a past Dline coach some would like to have return to Iowa.
There are trends for positions of overturn and maybe it is Erb being part of the problem I don't know, but maybe it's the recruiting v. actual coaching, when we look at these players.
Also, you can't lump these kids together as every kid/defection is different in nature.